Wireless communication systems provide User Equipment (UE), such as smartphones, tablet computers, and other media devices, wireless access to communication services and allow users to move about and communicate over the air with access communication networks. Data communication networks, such as Long Term Evolution (LTE), exchange data packets with UEs to provide services, such as internet access, media streaming, voice calls, and text messaging.
Using LTE, a UE detects and attaches to an LTE base station, such as an evolved NodeB (eNodeB). eNodeBs supports the exchange of signaling and data to LTE network elements, such as Serving Gateways (S-GWs), Mobility Management Entities (MMEs), Packet Data Network Gateways (P-GWs), Policy Charging Rules Functions (PCRFs), and other network elements. eNodeBs schedule resources to receive and transfer data and signaling for multiple UEs and may monitor network loading and congestion, signal strengths, and data retransmission rates to ensure a Quality-of-Service (QoS) level for media sessions.
Session Initiation Protocol (SIP) is a popular form of signaling to control the exchange of Internet Protocol (IP) packets between UEs for media sessions and other data transfer services. The UE registers an IP addresses with the SIP systems over the IP access networks and SIP control systems, such as an Internet Multimedia Subsystem (IMS). The SIP control systems use the registered IP addresses to exchange SIP messaging for the IP communications sessions. A UE may register with a SIP control system directly using various access systems, including LTE, Code Division Multiple Access (CDMA), Global System for Mobile Communications (GSM), Ethernet, and other access systems.
While an LTE eNodeB may support various UEs and traffic types, the LTE eNodeB does not have unlimited resources which may result in conflicts and packet loss. An IMS may use an alternative network to exchange SIP messaging, but unfortunately, current interactions between the LTE network and IMS are not effective for redirecting to a better, alternative network.